New start-up's advance allows you to go from fuzzy to focused AFTER snapping a photo.

That is the improbable-sounding achievement of a Silicon Valley start-up called Lytro. In October the company introduced a camera that eliminates the need to focus before taking a photograph. The device is the first commercial camera to capture light fields—the amount and direction of all the light making up a given scene. It collects vastly more data than standard digital cameras can, by using sensors and software that once would have required a supercomputer to support.

Comparing the $399 Lytro camera with conventional digital snapshooters is tricky. Although all cameras capture color and intensity, the Lytro device can also record the direction of 11 million light rays in one photograph. Exactly how its sensors do this is proprietary information, but the resulting trove of data allows users to focus a fuzzy photograph at any point after taking it, or even to shift the focus at will from an object in the foreground to one in the background and vice versa.

Company founder Ren Ng developed the technology as a graduate student at Stanford University, where researchers first captured light fields more than 15 years ago using hundreds of cameras linked to a supercomputer. “The concept of a light field camera has been around for decades,” says optics.org editor in chief Michael Hatcher. “What Lytro has done is bring together the optics, the software, and the sensors and put all that together in a format you can hold in your hand.”